Extracted stay points:
laltitude	longitude	arriving time	leaving time
40.00754164583334 116.31993147916666 2009-06-12,22:11:16 2009-06-13,01:15:58
40.093139945500674 116.08225647148286 2009-06-13,03:51:23 2009-06-13,06:02:08
40.10130280465119 116.08367837674415 2009-06-13,07:39:29 2009-06-13,08:15:24
